From cf9b01b09a320de4afb8da8f2ec5002fd0441831 Mon Sep 17 00:00:00 2001
From: Christian Halstrick <christian.halstrick@sap.com>
Date: Wed, 23 Jul 2014 15:30:06 +0200
Subject: [PATCH] Handle initial checkout correctly

As described in native gits file "git-read-tree.txt" git has in a
special mode when doing the "initial" checkout. "Initial" means that the
index is empty before the checkout. This was not handled correctly in
JGit and is fixed in this commit. Also see
https://github.com/git/git/blob/master/Documentation/git-read-tree.txt#L181

Change-Id: I9b9d1bd9ebf349cfca420c891c7b099a18d07ba4
---
 .../jgit/lib/DirCacheCheckoutTest.java        | 19 +++++++++++++++++++
 .../jgit/dircache/DirCacheCheckout.java       | 15 +++++++++++----
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java
index afbad6ab2..f7e6fa9b7 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java
@@ -72,6 +72,8 @@
 import org.eclipse.jgit.errors.CorruptObjectException;
 import org.eclipse.jgit.errors.NoWorkTreeException;
 import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.junit.TestRepository.BranchBuilder;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.treewalk.FileTreeIterator;
 import org.eclipse.jgit.treewalk.TreeWalk;
@@ -213,6 +215,23 @@ public void testResetHardFromIndexEntryWithoutFileToTreeWithoutFile()
 		assertIndex(mkmap("x", "x"));
 	}
 
+	/**
+	 * Test first checkout in a repo
+	 *
+	 * @throws Exception
+	 */
+	@Test
+	public void testInitialCheckout() throws Exception {
+		Git git = new Git(db);
+
+		TestRepository<Repository> db_t = new TestRepository<Repository>(db);
+		BranchBuilder master = db_t.branch("master");
+		master.commit().add("f", "1").message("m0").create();
+		assertFalse(new File(db.getWorkTree(), "f").exists());
+		git.checkout().setName("master").call();
+		assertTrue(new File(db.getWorkTree(), "f").exists());
+	}
+
 	private DirCacheCheckout resetHard(RevCommit commit)
 			throws NoWorkTreeException,
 			CorruptObjectException, IOException {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
index 80dda8eb8..4b0d58600 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
@@ -110,6 +110,8 @@ public class DirCacheCheckout {
 
 	private ArrayList<String> toBeDeleted = new ArrayList<String>();
 
+	private boolean emptyDirCache;
+
 	/**
 	 * @return a list of updated paths and objectIds
 	 */
@@ -168,6 +170,7 @@ public DirCacheCheckout(Repository repo, ObjectId headCommitTree, DirCache dc,
 		this.headCommitTree = headCommitTree;
 		this.mergeCommitTree = mergeCommitTree;
 		this.workingTree = workingTree;
+		this.emptyDirCache = (dc == null) || (dc.getEntryCount() == 0);
 	}
 
 	/**
@@ -716,7 +719,8 @@ void processEntry(CanonicalTreeParser h, CanonicalTreeParser m,
 			 * 	        0 nothing    nothing  nothing        (does not happen)
 			 * 	        1 nothing    nothing  exists         use M
 			 * 	        2 nothing    exists   nothing        remove path from index
-			 * 	        3 nothing    exists   exists   yes   keep index
+			 * 	        3 nothing    exists   exists   yes   keep index if not in initial checkout
+			 *                                               , otherwise use M
 			 * 	          nothing    exists   exists   no    fail
 			 * </pre>
 			 */
@@ -743,9 +747,12 @@ else if (m == null)
 				// in the index there is nothing (e.g. 'git rm ...' was
 				// called before). Ignore the cached deletion and use what we
 				// find in Merge. Potentially updates the file.
-				if (equalIdAndMode(hId, hMode, mId, mMode))
-					keep(dce);
-				else
+				if (equalIdAndMode(hId, hMode, mId, mMode)) {
+					if (emptyDirCache)
+						update(name, mId, mMode);
+					else
+						keep(dce);
+				} else
 					conflict(name, dce, h, m);
 			}
 		} else {